/**
 * 返回当前时间戳
 * @returns {number}
 */
export function getTime()
{
  return Math.floor(Date.now()/1000);
}

export function formatDate(format,timestamp){
  return date(format,timestamp)
}

export function resetDate(format,datetime){
  var d = new Date(datetime);
  return formatDate(format,d);
}


/**
 * 日期格式化
 * @param format 一般的Y-m-d H:i:s
 * @param timestamp
 * @returns {*}
 */

export default function date(format, timestamp) {
  //var that = this;
  var jsdate, f;
  // Keep this here (works, but for code commented-out below for file size reasons)
  // var tal= [];

  var txt_words = [
    'Sun', 'Mon', 'Tues', 'Wednes', 'Thurs', 'Fri', 'Satur',
    'January', 'February', 'March', 'April', 'May', 'June',
    'July', 'August', 'September', 'October', 'November', 'December'
  ];
  // trailing backslash -> (dropped)
  // a backslash followed by any character (including backslash) -> the character
  // empty string -> empty string
  var formatChr = /\\?(.?)/gi;
  var formatChrCb = function (t, s) {
    return f[t] ? f[t]() : s;
  };
  var _pad = function (n, c) {
    n = String(n);
    while (n.length < c) {
      n = '0' + n;
    }
    return n;
  };
  f = {
    // Day
    d: function () {
      // Day of month w/leading 0; 01..31
      return _pad(f.j(), 2);
    },
    D: function () {
      // Shorthand day name; Mon...Sun
      return f.l()
        .slice(0, 3);
    },
    j: function () {
      // Day of month; 1..31
      return jsdate.getDate();
    },
    l: function () {
      // Full day name; Monday...Sunday
      return txt_words[f.w()] + 'day';
    },
    N: function () {
      // ISO-8601 day of week; 1[Mon]..7[Sun]
      return f.w() || 7;
    },
    S: function () {
      // Ordinal suffix for day of month; st, nd, rd, th
      var j = f.j();
      var i = j % 10;
      if (i <= 3 && parseInt((j % 100) / 10, 10) == 1) {
        i = 0;
      }
      return ['st', 'nd', 'rd'][i - 1] || 'th';
    },
    w: function () {
      // Day of week; 0[Sun]..6[Sat]
      return jsdate.getDay();
    },
    z: function () {
      // Day of year; 0..365
      var a = new Date(f.Y(), f.n() - 1, f.j());
      var b = new Date(f.Y(), 0, 1);
      return Math.round((a - b) / 864e5);
    },

    // Week
    W: function () {
      // ISO-8601 week number
      var a = new Date(f.Y(), f.n() - 1, f.j() - f.N() + 3);
      var b = new Date(a.getFullYear(), 0, 4);
      return _pad(1 + Math.round((a - b) / 864e5 / 7), 2);
    },

    // Month
    F: function () {
      // Full month name; January...December
      return txt_words[6 + f.n()];
    },
    m: function () {
      // Month w/leading 0; 01...12
      return _pad(f.n(), 2);
    },
    M: function () {
      // Shorthand month name; Jan...Dec
      return f.F()
        .slice(0, 3);
    },
    n: function () {
      // Month; 1...12
      return jsdate.getMonth() + 1;
    },
    t: function () {
      // Days in month; 28...31
      return (new Date(f.Y(), f.n(), 0))
        .getDate();
    },

    // Year
    L: function () {
      // Is leap year?; 0 or 1
      var j = f.Y();
      return j % 4 === 0 & j % 100 !== 0 | j % 400 === 0;
    },
    o: function () {
      // ISO-8601 year
      var n = f.n();
      var W = f.W();
      var Y = f.Y();
      return Y + (n === 12 && W < 9 ? 1 : n === 1 && W > 9 ? -1 : 0);
    },
    Y: function () {
      // Full year; e.g. 1980...2010
      return jsdate.getFullYear();
    },
    y: function () {
      // Last two digits of year; 00...99
      return f.Y()
        .toString()
        .slice(-2);
    },

    // Time
    a: function () {
      // am or pm
      return jsdate.getHours() > 11 ? 'pm' : 'am';
    },
    A: function () {
      // AM or PM
      return f.a()
        .toUpperCase();
    },
    B: function () {
      // Swatch Internet time; 000..999
      var H = jsdate.getUTCHours() * 36e2;
      // Hours
      var i = jsdate.getUTCMinutes() * 60;
      // Minutes
      // Seconds
      var s = jsdate.getUTCSeconds();
      return _pad(Math.floor((H + i + s + 36e2) / 86.4) % 1e3, 3);
    },
    g: function () {
      // 12-Hours; 1..12
      return f.G() % 12 || 12;
    },
    G: function () {
      // 24-Hours; 0..23
      return jsdate.getHours();
    },
    h: function () {
      // 12-Hours w/leading 0; 01..12
      return _pad(f.g(), 2);
    },
    H: function () {
      // 24-Hours w/leading 0; 00..23
      return _pad(f.G(), 2);
    },
    i: function () {
      // Minutes w/leading 0; 00..59
      return _pad(jsdate.getMinutes(), 2);
    },
    s: function () {
      // Seconds w/leading 0; 00..59
      return _pad(jsdate.getSeconds(), 2);
    },
    u: function () {
      // Microseconds; 000000-999000
      return _pad(jsdate.getMilliseconds() * 1000, 6);
    },

    // Timezone
    e: function () {
      // Timezone identifier; e.g. Atlantic/Azores, ...
      // The following works, but requires inclusion of the very large
      // timezone_abbreviations_list() function.
      /*              return that.date_default_timezone_get();
       */
      throw 'Not supported (see source code of date() for timezone on how to add support)';
    },
    I: function () {
      // DST observed?; 0 or 1
      // Compares Jan 1 minus Jan 1 UTC to Jul 1 minus Jul 1 UTC.
      // If they are not equal, then DST is observed.
      var a = new Date(f.Y(), 0);
      // Jan 1
      var c = Date.UTC(f.Y(), 0);
      // Jan 1 UTC
      var b = new Date(f.Y(), 6);
      // Jul 1
      // Jul 1 UTC
      var d = Date.UTC(f.Y(), 6);
      return ((a - c) !== (b - d)) ? 1 : 0;
    },
    O: function () {
      // Difference to GMT in hour format; e.g. +0200
      var tzo = jsdate.getTimezoneOffset();
      var a = Math.abs(tzo);
      return (tzo > 0 ? '-' : '+') + _pad(Math.floor(a / 60) * 100 + a % 60, 4);
    },
    P: function () {
      // Difference to GMT w/colon; e.g. +02:00
      var O = f.O();
      return (O.substr(0, 3) + ':' + O.substr(3, 2));
    },
    T: function () {
      return 'UTC';
    },
    Z: function () {
      // Timezone offset in seconds (-43200...50400)
      return -jsdate.getTimezoneOffset() * 60;
    },

    // Full Date/Time
    c: function () {
      // ISO-8601 date.
      return 'Y-m-d\\TH:i:sP'.replace(formatChr, formatChrCb);
    },
    r: function () {
      // RFC 2822
      return 'D, d M Y H:i:s O'.replace(formatChr, formatChrCb);
    },
    U: function () {
      // Seconds since UNIX epoch
      return jsdate / 1000 | 0;
    }
  };


  var $date = function (format, timestamp) {
    //that = this;
    jsdate = (timestamp === undefined ? new Date() : // Not provided
      (timestamp instanceof Date) ? new Date(timestamp) : // JS Date()
      new Date(Math.floor(timestamp) * 1000) // UNIX timestamp (auto-convert to int)
    );
    return format.replace(formatChr, formatChrCb);
  };
  return $date(format, timestamp);
}



// 获取某日期所在月的结束时间（23:59:59.999）
export function getMonthEndDate(dateStr) {
    const date = new Date(dateStr);

    // 获取当前月份的下一个月的第一天
    const nextMonth = new Date(date.getFullYear(), date.getMonth() + 1, 1);

    // 将日期设置为当前月最后一天的前一天
    nextMonth.setDate(nextMonth.getDate() - 1);

    // 设置时间为23:59:59.999
    nextMonth.setHours(23, 59, 59, 999);

    return nextMonth;
}

// 获取某日期所在月的开始时间（00:00:00.000）
export function getMonthStartDate(dateStr) {
    const date = new Date(dateStr);

    // 将日期设置为当前月的第一天
    const firstDayOfMonth = new Date(date.getFullYear(), date.getMonth(), 1);

    // 设置时间为00:00:00.000
    firstDayOfMonth.setHours(0, 0, 0, 0);

    return firstDayOfMonth;
}

// 获取某日期上月的开始时间（00:00:00.000）
export function getPrevMonthStartDate(dateStr) {
    const date = new Date(dateStr);

    // 获取上个月的第一天
    const firstDayOfPreviousMonth = new Date(date.getFullYear(), date.getMonth() - 1, 1);

    // 设置时间为00:00:00.000
    firstDayOfPreviousMonth.setHours(0, 0, 0, 0);

    return firstDayOfPreviousMonth;
}

// 获取某日期上月的结束时间（23:59:59.999）
export function getPrevMonthEndDate(dateStr) {
    const date = new Date(dateStr);

    // 获取上个月的下一个月的第一天
    const firstDayOfNextMonth = new Date(date.getFullYear(), date.getMonth(), 1);

    // 获取上个月的最后一天
    firstDayOfNextMonth.setDate(0);

    // 设置时间为23:59:59.999
    firstDayOfNextMonth.setHours(23, 59, 59, 999);

    return firstDayOfNextMonth;
}

